A typical drain for a kitchen sink usually includes a strainer housing carried in a drain hole in a bottom of the sink, and a strainer basket removably carried in the strainer housing. The strainer housing typically includes a circular flange supported around the drain hole on an upper surface of the sink bottom, and a cylindrical cup depending downwardly from the flange through the drain hole. When a pan is placed in the sink, it may cover the drain entirely and thereby create a seal with the sink bottom around the drain, such that running water backs up in the sink and does not flow down the drain. Also, the strainer basket is easily clogged with debris, thereby causing water to back up in the sink.